Orthodontic anchor

ABSTRACT

An orthodontic implant comprised of one or two bony attachments, and, if there are two, one is smaller and affixed to the opposite end of the emerging portion, while the other utilizes a screw placed through an aperture. The smaller affixed portion is a tapered tac with the opposite emerging portion receiving an “O” ring removable cap onto which an adjustable rod can be contoured as needed after the implant has been affixed to bone.

BACKGROUND OF THE INVENTION

Orthodontic implants have become increasingly popular in the past fewyears because of the need for absolute anchorage and the diminishingcooperation patients are exhibiting. Two basic types of implants areavailable, namely the single screw placed in the dentoalveolar bonebetween tooth roots and the skeletal miniplate attached to basal boneapical and away from the proximity of the roots.

The advantages of the single screw implant with a variety of headdesigns, depending on the manufacturer, include ease of placement, whichcan be performed by an orthodontist, and which is atraumatic and is lessexpensive. The disadvantages include possible root penetration, poorbony anchorage, limitation on the type of force vectors which can beutilized, bony insertion at an undesirable angle in order to avoid rootdamage, insertion more apically than desired so as to avoid root damageand the tendency to unscrew if the created moment tends to unwind thescrew. Another disadvantage that frequently surfaces, particularly inthe mandibular arch, is soft tissue proliferation at the emergence ofthe implant. The resultant hyperplastic tissue can sometimes completelyengulf the exposed end making monthly adjustments difficult. By placingthe implant emergence at or near the mucogingival junction, which isoften difficult because of root proximity, this undesirable soft tissueresponse is avoidable.

The advantages of the multiscrew skeletal miniplate include betteranchorage and hence larger magnitudes of force application, no orgreatly reduced potential for root damage, better ability to withstandall forces in all directions and reduced chance of implant failure. Thesoft tissue response is much improved because emergence can approximatethe mucogingival junction. The disadvantages include cost, moredifficult placement and accompanying surgery and longer post-operativerecovery. Placement will generally require the skills of an oralsurgeon.

BRIEF SUMMARY OF THE INVENTION

The orthodontic implant according to this invention is designed for easeof insertion, adjustability of a wire or tube affixed to a cap which isheld onto the emerging portion of the implant, fixation into bone at oneor two separate locations, one of said fixations being a tapered tacover which a tool can be placed, and wherein a few light blows with asmall hammer drive the tac a few millimeters into cortical bone. If onlyone fixation point is utilized, the tac is omitted. The second fixationpoint, if two penetrations are desired, is located more apically andhence reducing the danger of root damage, is home to a large diameterand longer bony screw which is inserted through the appropriately sizedaperture.

The cap being internally angular, as is the emerging portion of theanchor, can be rotated in a number of directions hence changing thelocation and direction of the wire or tube permanently affixed thereto.The cap is easily removed from the implant thus affording thepractitioner the ability to modify the length and configuration of theattached or emerging wire while the cap is securely maintained by an “O”ring fitting into a groove within the implant head.

A special sliding tube fits onto the arch wire thus permitting theclinician to stabilize the sliding tube wherever desired and thendeliver forces directly along the archwire if so desired.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a perspective view of an orthodontic anchor in accordance withthis invention;

FIGS. 2A, 2B and 2C are top plan views of modified designs of the plateelement of the anchor;

FIG. 3 is a perspective view showing placement of the anchor;

FIG. 4 is a side elevational view with a cross-sectional view of theanchor;

FIG. 4A is an enlarged perspective view of a portion of the anchor;

FIGS. 5, 6, 7 and 8 show operation of the anchor in connection with anarchwire;

FIG. 9 is a partial exploded view of a modification of the anchor;

FIGS. 10A, 10B and 10C depict different applications of the anchor “O”ring;

FIG. 11 is a perspective view of a modification of the implant;

FIGS. 12, 13 and 14 show modified versions of the cap securing means;and

FIG. 15 is an elevational view of a further modification of the anchor.

DETAILED DESCRIPTION OF THE INVENTION

In accordance with this invention, the orthodontic anchor or implant isviewed in FIG. 1 and comprises plate 1 which is a thin sheet ofbiocompatible material such as titanium through which at its moreocclusal opening a shaft of material is inserted and attached theretowhich has at its bony surface side a tapered, grooved, short tac 2 whichcan penetrate the dense, outer layer of cortical bone. Tac 2 is about 3mm in length and about 1.4 mm in diameter at its widest dimension.Emerging from the gingival side of the body is angular head 3 withgroove 4 located near its distal end. Fitting over angular head 3 is cap5 which is also internally angular so as to fit snugly over angular head3. An “O” ring 6 is contained within cap 5 by a groove formed on theinner surface of cap 5 such that when cap 5 is pressed onto angular head3 the “O” ring locks into groove 4 in angular head 3. An extension wire7 is either attached to the top of cap 5 directly or extends from anappropriately sized angular tube which has been attached to the cap.This extension wire permits the clinician to adjust the wire into anumber of configurations and locations. Likewise by rotating cap 5before placement on angular head 3, the position of extension wire 7 canbe varied. Also, major anchor screw 8 is inserted through anappropriately sized orifice 9 formed in plate 1 and screwed deeper intothe bone after tac 2 has been used to position and stabilize plate 1.Major anchor screw 8 is similar in size to a conventional single screwimplant and is approximately 5-7 mm in length and 1.7-2.2 mm in diameterat its largest dimension.

FIGS. 2A, 2B and 2C show modifications to plate 1 such that thin,bendable projections 10 are added for additional stabilization byutilizing osseointegration on, around and over these thin projections.

FIG. 3 depicts three mandibular posterior teeth with plate 1 placed suchthat head 3 is emerging at the mucogingival junction 11 with largerorifice 9 located more apically where there is greater distance betweenthe roots.

FIGS. 4 and 4A show all aspects of the implant according to thisinvention. A layer of dense cortical bone 12 is penetrated by both tac 2and screw 8 while looser medulary bone 13 is pierced primarily by screw8. The implant is placed under soft tissue periostium 14 while cap 5enters slightly into the soft overlying gingival connective tissue 15.Archwire 16 is contained within bracket 17 which is in turn attached tothe buccal surface of a tooth 18. As shown in FIG. 4A, contouredextension wire 7 fits into an opening 19 on sliding tube 20 and isstabilized laterally by projection 21 which extends therefrom.

FIG. 5 is a buccal view of a clinical situation in which it is desirableto stabilize the more anterior teeth while moving the molar towardsthem. Sliding tube 20 fits onto the archwire 16 and is pressed againstbracket 17 by extension wire 7 held against archwire 16 by projection21. A force can then be applied from bicuspid tooth 22 or cuspid tooth23 to molar tooth 24 thereby permitting the molar tooth to slide onarchwire 16 through its own buccal tube 25.

FIG. 6 is an occlusal view of the same scenario with archwire 16extending through molar buccal tube 25 and onto which sliding tube 20,with its stabilizing projection 21, help contain extension wire 7.Sliding tube 20 is held firmly against bracket 17 by extension wire 7.Extension wire 7 is also attachable to archwire 16 by other known tubes,brackets and attachment wires.

FIG. 7 is a buccal view of a clinical situation in which it is desirableto stabilize the more posterior molar 24, while retracting the anteriorteeth including the cuspid 23. The extension wire 7 presses the slidingtube against molar buccal tube 25, thereby preventing molar mesialmovement while retracting the anterior teeth into the extraction site.

FIG. 8 shows an extruded molar and the insertion of cap 5 at a rotationresulting in extension wire 7 being approximately parallel to archwire16 rather than perpendicular to the archwire as depicted in FIGS. 5-7.With extension wire 7 in this location, vertical forces 26 can bepositioned anywhere along extension wire 7 to direct the desiredintrusion force.

FIGS. 9, 10A, 10B and 10C show a modification to the “O” ring-capretention mechanism in that the “O” ring fits on the outside of cap 5rather than inside cap 5 with the cap modified to only contain, in the“O” ring region, two contoured pillars 27. An elliptically shaped “O”ring shown in FIG. 10C, thicker in its short axis and thinner in itslong axis, encircles cap 5 and is held in place by inwardly bowedpillars 27 which interconnect two separate sections of cap 5, as shownin FIG. 9. The thicker sections of the “O” ring would extend into groove4.

FIG. 11 is similar to FIG. 4 and shows a different head extendingthrough the gingival mucosa. Occlusally to the head is attached gingival28 while apically to the head is loose connective tissue 29. The taperedimplant 2 is inserted at the mucogingival junction 11. The extrudingportion of the implant, as depicted in FIG. 11, is a modification ofthat described in FIG. 1 in that cap 5 is open at both ends and ispositioned below groove 4 and “O” ring 30 fills groove 4. “O” ring 30 islarger in diameter than the outer dimension of cap 5 thereby preventingthe displacement of cap 5.

FIGS. 12, 13 and 14 show three additional ways cap 5 is secured to theextruded portion of the implant. In FIG. 12, flexible wire 31 ispermanently attached to cap 5 at one end while free to move at the otherend. The spring action of the wire keeps cap 5 affixed to the anchorhead by engaging in groove 4. In FIG. 13, a flexible ring is insertedinto groove 4 and is removed at will by inserting an instrument into thesmall portion 32. In FIG. 14, hooks 33 are an integral part of cap 5 andan elastomeric chain 34 is attached from hook to hook with the centerhole fitting around shaft 3 and resting in groove 4.

FIG. 15 depicts a single anchor without plate 1 designed to be insertedsingularly into bone and with a protruding head and cap as shown inFIGS. 11-14. The anchor includes bony screw portion 2, long angularshafts 3, short groove 4 and small angular portion 3 a. A cap, as shownin FIGS. 12 and 14, fits over long angular shaft 3. An “O” ring disposedin groove 4 or one of the attaching means of FIGS. 5, 12, 13 or 14 areadaptable to secure the cap in place.

1. An orthodontic anchor comprising a tac piercing bone, an anchor screwspaced from piercing bone more deeply than said tac, and said tac andsaid screw interconnected by a plate.
 2. An orthodontic anchor accordingto claim 1 wherein said tac projects from said bone by means of anangular head.
 3. An orthodontic anchor according to claim 2 wherein afirst groove is formed in said angular head.
 4. An orthodontic anchoraccording to claim 3 wherein a cap envelopes said angular head.
 5. Anorthodontic anchor according to claim 4 wherein a second groove isformed on the inner surface of said cap.
 6. An orthodontic anchoraccording to claim 5 wherein an “O” ring is disposed in said first andsecond grooves.
 7. An orthodontic anchor according to claim 4 wherein anextension wire is secured to said cap at one end and to an archwire atthe other end.
 8. An orthodontic anchor according to claim 7 whereinsaid extension wire extends from said cap omnidirectionally.
 9. Anorthodontic anchor according to claim 2 wherein a cap envelopes saidangular head and said cap is formed of two sections interconnected bymeans of a pair of pillars.
 10. An orthodontic anchor according to claim9 wherein an elliptically shaped “O” ring extends around said pillars.11. An orthodontic anchor according to claim 10 wherein saidelliptically shaped “O” ring is thicker along one axis and the axisdisposed perpendicular thereto.
 12. An orthodontic anchor according toclaim 11 wherein a groove is formed in said angular head.
 13. Anorthodontic anchor according to claim 12 wherein said thicker sectionsare disposed in said groove.
 14. An orthodontic anchor according toclaim 7 wherein said extension wire is secured to said archwire by meansof a sliding tube.
 15. An orthodontic anchor according to claim 14wherein a projection extends from said sliding tube and said extensionwire is attached to said projection.
 16. An orthodontic anchorcomprising bony screw portion, an angular shaft extending coaxially fromsaid screw portion, a groove extending coaxially from angular shaft, asmall angular portion extending from said groove, and an angular capopen at both ends and enveloping said angular shaft.
 17. An orthodonticanchor according to claim 16 wherein an “O” ring is disposed in saidgroove.
 18. An orthodontic anchor according to claim 16 wherein aflexible wire is attached to said cap.
 19. An orthodontic anchoraccording to claim 1 wherein a flexible clamp interconnects said cap andsaid angular shaft.
 20. An orthodontic anchor according to claim 16wherein a pair of hooks extend from said cap and an elastomeric chain isattached at its ends respectively to said hooks.
 21. An orthodonticanchor according to claim 4 wherein an angular tube is secured to saidcap.
 22. An orthodontic anchor according to claim 21 wherein an angularextension wire is secured to said angular tube.